Over half of older adults hospitalized for heart disease also have reduced kidney function

Over half of older adults hospitalized for heart disease also have reduced kidney function, suggests a study in the July Journal of the American Society of Nephrology.

Although it has recently been appreciated that patients with kidney disease are at greatly increased risk of developing cardiovascular disease, it now appears that patients with heart disease should be considered a high-risk group and targeted for evaluation and treatment of chronic kidney disease (CKD), suggest Dr. William M. McClellan and colleagues of Georgia Medical Care Foundation, Atlanta.

Dr. McClellan and his fellow researchers analyzed nearly 15,000 Medicare managed care patients hospitalized for heart disease. Roughly half the patients had acute myocardial infarction (AMI, or "heart attack") while the rest had congestive heart failure (CHF). Average age was 74 years for the AMI patients and 76 years for the CHF patients.

A review of medical records showed that most of the heart disease patients had moderately reduced kidney function, or CKD. This condition was found in 52 percent of AMI patients and 60 percent of CHF patients. However, CKD was recognized in the hospital in only about 20 percent of patients.

Patients with CKD had worse outcomes than those with normal kidney function. They were at higher risk of being readmitted to the hospital within one month, especially those with CHF. Patients with CKD were also more likely to die within one year after leaving the hospital. In the AMI group, risk of death was about three times higher in patients with CKD than in those with normal kidney function.

Follow-up data on 1,150 patients were analyzed to assess the risk of developing end-stage renal disease (ESRD), or kidney failure requiring dialysis or transplantation. For heart disease patients with CKD, the rate of ESRD was two to three-and-one-half percent. In contrast, none of the patients without CKD went on to develop ESRD.

When CKD is discovered, effective treatments can slow or prevent progressive kidney disease and ESRD. Still, many patients with CKD go unrecognized. Screening tests have been recommended for certain high-risk groups, such as patients with diabetes and high blood pressure, minority groups, and the elderly.

Patients with heart disease might be an important addition to this list, the new results suggest. Over half of elderly patients hospitalized for AMI or CHF have reduced kidney function. This problem is often undiagnosed while the patient is in the hospital, and may progress to ESRD within a relatively short time.

Patients with heart disease should be recognized as a high-risk group for kidney disease, Dr. McClellan and colleagues suggest. They are testing a quality improvement program to increase detection and treatment of CKD in patients hospitalized for AMI or CHF.